Hi Tim,
The D3 software from Blackbox is being sold as a single unit for all ECU variations. I'm hoping that once they get the release of the software out of the way they do look at more modular pricing for RCL users. I for one am very interested as it means there's a path forward from my D2 that's not a Toyota or a Nissan.
The web price for the software (you also need the hardware) is GBP1350. Given the amount of systems it has to work with a modular price may not be any less.
This is the info page:
http://www.blackbox-solutions.com/shop/help/SM129.html